Method and device for determining the position of at least one second transmitting and receiving device in respect of a first transmitting and receiving device in a passive access control system operating in the GHZ range

• US 20040125013A1
• Filed: 10/21/2003
• Published: 07/01/2004
• Est. Priority Date: 10/25/2002
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Haselsteiner, Mario, Stielow, Arnd, Klement, Thomas, Hofbeck, Klaus, Rosel, Birgit
• Granted Patent: US 6,909,396 B2
• Time in Patent Office: Days
• US Class Current: 342/125
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: G01S 13/88 Radar or analogous systems specially adapted for specific applications electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00
• CPC Class Codes: G01S 7/352 Receivers
• CPC Class Codes: G07C 2209/63 Comprising locating means for detecting the position of the data carrier, i.e. within the vehicle or within a certain distance from the vehicle
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

A method for determining the position of at least one second transmitting and receiving device (3) in respect of a first transmitting and receiving device in a passive access control system operating in the GHz range, comprising the steps of using a radar method, wherein signals (f1, f2) are received in the first transmitting and receiving device on the left-hand side and right-hand side of a modulation frequency (f_mod), determining the distance of two signals (f1, f2) closest to the left-hand side and right-hand side modulation frequency (f_mod) wherein the distance is proportional to the distance between the first transmitting and receiving device and at least one second transmitting and receiving device (3), so that multipath propagations are not taken into consideration.

Claims

1. A method for determining the position of at least one second transmitting and receiving device in respect of a first transmitting and receiving device in a passive access control system operating in the GHz range, comprising the steps of:

a) using a radar method, particularly an FM-CW radar method, by which signals are received in the first transmitting and receiving device on the left-hand side and right-hand side of a modulation frequency, and

b) determining the distance of two signals closest to the left-hand side and right-hand side modulation frequency, wherein the distance of the two signals is proportional to the distance between the first transmitting and receiving device and at least the second transmitting and receiving device so that multipath propagations are not taken into consideration.

2. The method according to claim 1, wherein the distance of the signals is determined by means of at least one bandpass filter wherein in a first measurement, starting out with a predefined lowest bandwidth and if signals are not detected within this bandwidth, the distance of the bottom and top limits of at least one bandpass filter is increased by the modulation frequency for the next measurement.

3. The method according to claim 2, wherein each subsequent measurement takes place with a predefined bandwidth in each case.

4. The method according to claim 3, wherein different ranges are assigned to different top and bottom measurements.

5. A transmitting and receiving device for determining the position of at least one further transmitting and receiving device, wherein the transmitting and receiving device is embodied as an FM-CW radar transmitting and receiving device and comprises at least one bandpass filter to determine the distance of two signals lying closest to the left-hand side and right-hand side of the modulation frequency.

6. The transmitting and receiving device according to claim 5, wherein the at least one bandpass filter can be varied to perform consecutive measurements with different increasing bandwidths in each case.

7. The transmitting and receiving device according to claim 5, wherein the transmitting and receiving device has two bandpass filters to detect signals lying on the left-hand side and right-hand side of the modulation frequency, respectively.

8. An arrangement comprising:

a first transmitting and receiving device,

a second transmitting and receiving device, wherein

the first transmitting and receiving device can determine the position of the at least second transmitting and receiving device,

the first transmitting and receiving device is embodied as an FM-CW radar transmitting and receiving device and comprises at least one bandpass filter to determine the distance of two signals lying closest to the left-hand side and right-hand side of the modulation frequency,

the first transmitting and receiving device is embodied as the base station of a vehicle, and wherein

the at least second transmitting and receiving device as an ID transmitter.

9. The arrangement according to claim 8, wherein the second transmitting and receiving device is embodied as a reflector that returns the signals of the first transmitting and receiving device in a modulated way.

10. The arrangement according to claim 8, wherein the at least one bandpass filter can be varied to perform consecutive measurements with different increasing bandwidths in each case.

11. The arrangement according to claim 8, wherein the first transmitting and receiving device has two bandpass filters to detect signals lying on the left-hand side and right-hand side of the modulation frequency, respectively.